Re: [Qemu-devel] [PATCH 06/11] qmp: Add an implementation wrapper for qmp_drive_backup

[Max Reitz <mreitz@redhat.com>]

On 2015-03-17 at 15:16, John Snow wrote:
>
>
> On 03/17/2015 02:51 PM, Max Reitz wrote:
>> On 2015-03-04 at 23:15, John Snow wrote:
>>> We'd like to be able to specify the callback given to backup_start
>>> manually in the case of transactions, so split apart qmp_drive_backup
>>> into an implementation and a wrapper.
>>>
>>> Switch drive_backup_prepare to use the new wrapper, but don't overload
>>> the callback and closure yet.
>>>
>>> This is kind of gross, but we need to forward-declare the wrapper for
>>> the drive_backup transaction to be able to use. I could try moving
>>> the transaction blocks lower instead, but I wanted (for v1, at least)
>>> to minimize code movement so that the core changes were easiest to see.
>>>
>>> If anyone has suggestions on organization, please suggest them.
>>>
>>> Signed-off-by: John Snow <jsnow@redhat.com>
>>> ---
>>>   blockdev.c | 77
>>> ++++++++++++++++++++++++++++++++++++++++++++++----------------
>>>   1 file changed, 58 insertions(+), 19 deletions(-)
>>>
>>> diff --git a/blockdev.c b/blockdev.c
>>> index 3153ee7..9e3b9e9 100644
>>> --- a/blockdev.c
>>> +++ b/blockdev.c
>>> @@ -1449,6 +1449,19 @@ void
>>> undo_transaction_wrapper(BlkTransactionState *common)
>>>       blk_put_transaction_state(common);
>>>   }
>>> +static void _drive_backup(const char *device, const char *target,
>>
>> Please don't use leading underscores. (Please.)
>>
>> Just call it do_drive_backup() or something.
>>
>> Other than that, I'm okay with a forward-declaration; if you want to
>> move it, but I'd be fine with moving the code, too.
>>
>> With _drive_backup() being called do_drive_backup():
>>
>> Reviewed-by: Max Reitz <mreitz@redhat.com>
>>
>
> Moving the code around might be better, it just makes for a much 
> noisier patch. I made my decisions for v1 to keep code disturbed the 
> least.
>
> Once more critiques roll in I will decide what to do.
>
> I'll replace with "do_drive_backup" unless you can think of a nice 
> three-letter word to replace "do" so that I don't even have to perturb 
> the alignment context ;)

Well, you're still prepending "static", so I think you won't get around 
perturbing the context :-)

Max

>>> +                          bool has_format, const char *format,
>>> +                          enum MirrorSyncMode sync,
>>> +                          bool has_mode, enum NewImageMode mode,
>>> +                          bool has_speed, int64_t speed,
>>> +                          bool has_bitmap, const char *bitmap,
>>> +                          bool has_on_source_error,
>>> +                          BlockdevOnError on_source_error,
>>> +                          bool has_on_target_error,
>>> +                          BlockdevOnError on_target_error,
>>> +                          BlockCompletionFunc *cb, void *opaque,
>>> +                          Error **errp);
>>> +
>>>   /* internal snapshot private data */
>>>   typedef struct InternalSnapshotState {
>>>       BlkTransactionState common;
>>> @@ -1768,15 +1781,16 @@ static void
>>> drive_backup_prepare(BlkTransactionState *common, Error **errp)
>>>       state->aio_context = bdrv_get_aio_context(bs);
>>>       aio_context_acquire(state->aio_context);
>>> -    qmp_drive_backup(backup->device, backup->target,
>>> -                     backup->has_format, backup->format,
>>> -                     backup->sync,
>>> -                     backup->has_mode, backup->mode,
>>> -                     backup->has_speed, backup->speed,
>>> -                     backup->has_bitmap, backup->bitmap,
>>> -                     backup->has_on_source_error,
>>> backup->on_source_error,
>>> -                     backup->has_on_target_error,
>>> backup->on_target_error,
>>> -                     &local_err);
>>> +    _drive_backup(backup->device, backup->target,
>>> +                  backup->has_format, backup->format,
>>> +                  backup->sync,
>>> +                  backup->has_mode, backup->mode,
>>> +                  backup->has_speed, backup->speed,
>>> +                  backup->has_bitmap, backup->bitmap,
>>> +                  backup->has_on_source_error, 
>>> backup->on_source_error,
>>> +                  backup->has_on_target_error, 
>>> backup->on_target_error,
>>> +                  NULL, NULL,
>>> +                  &local_err);
>>>       if (local_err) {
>>>           error_propagate(errp, local_err);
>>>           return;
>>> @@ -2717,15 +2731,18 @@ out:
>>>       aio_context_release(aio_context);
>>>   }
>>> -void qmp_drive_backup(const char *device, const char *target,
>>> -                      bool has_format, const char *format,
>>> -                      enum MirrorSyncMode sync,
>>> -                      bool has_mode, enum NewImageMode mode,
>>> -                      bool has_speed, int64_t speed,
>>> -                      bool has_bitmap, const char *bitmap,
>>> -                      bool has_on_source_error, BlockdevOnError
>>> on_source_error,
>>> -                      bool has_on_target_error, BlockdevOnError
>>> on_target_error,
>>> -                      Error **errp)
>>> +static void _drive_backup(const char *device, const char *target,
>>> +                          bool has_format, const char *format,
>>> +                          enum MirrorSyncMode sync,
>>> +                          bool has_mode, enum NewImageMode mode,
>>> +                          bool has_speed, int64_t speed,
>>> +                          bool has_bitmap, const char *bitmap,
>>> +                          bool has_on_source_error,
>>> +                          BlockdevOnError on_source_error,
>>> +                          bool has_on_target_error,
>>> +                          BlockdevOnError on_target_error,
>>> +                          BlockCompletionFunc *cb, void *opaque,
>>> +                          Error **errp)
>>>   {
>>>       BlockDriverState *bs;
>>>       BlockDriverState *target_bs;
>>> @@ -2837,9 +2854,15 @@ void qmp_drive_backup(const char *device, const
>>> char *target,
>>>           }
>>>       }
>>> +    if (cb == NULL) {
>>> +        cb = block_job_cb;
>>> +    }
>>> +    if (opaque == NULL) {
>>> +        opaque = bs;
>>> +    }
>>>       backup_start(bs, target_bs, speed, sync, bmap,
>>>                    on_source_error, on_target_error,
>>> -                 block_job_cb, bs, &local_err);
>>> +                 cb, opaque, &local_err);
>>>       if (local_err != NULL) {
>>>           bdrv_unref(target_bs);
>>>           error_propagate(errp, local_err);
>>> @@ -2850,6 +2873,22 @@ out:
>>>       aio_context_release(aio_context);
>>>   }
>>> +void qmp_drive_backup(const char *device, const char *target,
>>> +                      bool has_format, const char *format,
>>> +                      enum MirrorSyncMode sync,
>>> +                      bool has_mode, enum NewImageMode mode,
>>> +                      bool has_speed, int64_t speed,
>>> +                      bool has_bitmap, const char *bitmap,
>>> +                      bool has_on_source_error, BlockdevOnError
>>> on_source_error,
>>> +                      bool has_on_target_error, BlockdevOnError
>>> on_target_error,
>>> +                      Error **errp)
>>> +{
>>> +    _drive_backup(device, target, has_format, format, sync, has_mode,
>>> mode,
>>> +                  has_speed, speed, has_bitmap, bitmap,
>>> has_on_source_error,
>>> +                  on_source_error, has_on_target_error, 
>>> on_target_error,
>>> +                  NULL, NULL, errp);
>>> +}
>>> +
>>>   BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
>>>   {
>>>       return bdrv_named_nodes_list();
>>
>